74 DIPTERA OF NORTH AMERICA. 



S. T. palposa Loew. %. (Tab. II, fig. 9.) — Flava, abdoinine punc- 

 torum nigroruni seriebus quatuor picto, alis hyalinis luteo-fasciatis, vena 

 longitudinal! tertia nuda. 



Yellow, abdomen with four rows of black dots, wings byaline with luteous 

 bands and tbe tbird longitudinal vein bare. Long. corp. 0.26 — 0.27. 

 Long. al. 0.26. 



It is nearly allied to Tryp. arctii Deg., lappce Ccderli, etc. 

 Yellow; front brighter yellow, rather broad; frontal bristles black- 

 ish, the small bristles of the posterior orbit whitish. Antennas 

 yellow, descending a little beyond the middle of the face, their 

 third joint rather broad ; the bristle of the antennas apparently 

 bare, with the base slightly incrassated. Face a little receding, 

 excavated in the middle, so that the border of the mouth is pro- 

 jecting ; the furrows for the reception of the antennas rather flat. 

 Opening of the mouth very wide; proboscis thick and short; palpi 

 broad, rather large, with some small black bristles. Thorax with 

 a large glossy black spot in the middle of its anterior side ; its 

 upper side blackish, with the exception of the lateral and posterior 

 borders, and of a large triangular spot which rises from the poste- 

 rior border ; hairs whitish-yellow ; bristles blackish ; two of the 

 latter, inserted before the scutellum, are placed on larger black 

 dots, and two before them on smaller dots. Scutellum with four 

 bristles, yellow, only a little blackened at the base of the lateral 

 border. Metanotum black. Pleuras w f ith some brown spots, and 

 above the posterior coxas with a small black spot. The third, 

 fourth, and fifth segments of the abdomen have each at its anterior 

 border four small black spots, the intermediate ones being more 

 approximated ; the fifth segment is much prolonged, and has, 

 moreover, a black spot in each posterior corner. The rather coarse 

 hairs of the abdomen are yellowish on the first segments and the 

 anterior part of the middle ones, the remaining ones are black. 

 Legs yellow; anterior femora with black bristles on the under 

 side. The color of the picture of the wings is brownish-yellow in 

 my specimen, which is apparently a little faded ; it extends on the 

 costal border from the base to the tip of the first longitudinal vein, 

 and, on the first portion of this extent, reaches as far as the fourth 

 longitudinal vein, and on the second half as far as the third only. 

 From the tip of the first longitudinal vein a band runs over the 

 small transverse vein ; a second band runs from the costal border 

 over the posterior transverse vein ; these two bands become more 



